针对采用爆破破岩方式对金属矿山遗留矿柱进行回采存在安全性差与矿石损失率高的局限性,将具有无振动特征的高效静态破碎剂(High Range Static Cracking Agent,HSCA)引入遗留矿柱回采中.通过设计HSCA膨胀压应力测试试验与静力破岩试验,分析了HSCA径向膨胀压应力大小及其分布规律与水灰比的关系.分别从膨胀压应力分布特征、主裂纹定向控制方法与破岩时效性 3 个方面,论证了通过HSCA静力破岩实现金属矿山遗留矿柱安全低损回采的可行性.研究结果表明:当水灰比大于理论最优水灰比时,膨胀压应力随着水灰比的增大而减小.对于上向倾斜装药孔膨胀压应力沿孔底至孔口方向呈增大趋势,对于下向倾斜装药孔膨胀压应力则呈减小趋势.采用HSCA静力破岩对遗留矿柱进行回采,遗留矿柱主裂纹走向可通过对装药孔进行预切槽、增设诱导片或新增诱导孔等方式进行定向控制,进而有效降低非破岩区矿岩的再损伤.因此,对于不宜采用爆破破岩方式对遗留矿柱进行回采的区域,HSCA静力破岩不仅有利于保障遗留矿柱回采安全,而且可提高遗留矿柱回收率.研究成果可为进一步探索金属矿山遗留矿柱回采破岩新理论与新技术提供参考.
Experimental Study on Safe and Low Loss Recovery of Metal Mine Legacy Ore Pillars Based on HSCA Static Rock Breaking
Aim at the use of blasting to mining legacy ore pillars in metal mines has the limitations of poor safety and high ore loss rate,High Range Static Cracking Agent(HSCA)which has no vibration characteristics is introduced into the mining of legacy ore pillars.Through the design of HSCA expansion compressive stress tests and static rock breaking tests,the magnitude of HSCA radial expansion compressive stress and its distribution pattern in relation to the water-cement ratio were analyzed,and the feasibility of achieving the safe and low-loss mining of legacy pillars in metal mines through HSCA static rock breaking was demonstrated from the characteristics of the distribution of the expansion compressive stress,the method of con-trolling the orientation of the main crack,and the timeliness of rock breaking,respectively.The results show that when the wa-ter-cement ratio is larger than the theoretical optimum water-cement ratio,the expansion compressive stress decreases with the increase of the water-cement ratio.For an upwardly inclined borehole,the expansion compressive stress tends to increase from the bottom of the borehole towards the mouth of the borehole.Conversely,for a downward inclined hole,the expansion compres-sive stress tends to decrease.By using HSCA static rock breaking,the main crack direction of the legacy ore pillars can be con-trolled by pre-cutting slots in the charge holes,adding induced sheet or induced holes,which can effectively reduce the re-inju-ry of the non-rock-breaking area of the ore rock.Therefore,for the areas where blasting is not suitable for mining the legacy ore pillars,using HSCA static rock breaking is not only conducive to ensuring the safety of legacy pillar mining,but also improves the legacy pillar mining rate.The study results can provide reference for further exploring the new rock breaking theory and technology of mining the legacy ore pillars in metal mines.
static rock breakinglegacy ore pillarsexpansion compression stressmain cracktimeliness
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